The key is the roast corn broth.
Roast Corn Chawan Mushi
340g/12oz roasted corn stock
156g/5.5oz/3 large eggs
16g/5/8oz/1T smoked soy sauce
Place a steamer on high heat and bring to a full simmer. Use a fork to lightly blend the eggs and the soy sauce. Stir in the roasted corn stock and then strain the mixture through a fine mesh strainer. Some egg particles will be caught in the strainer, that is ok. Pour 200g/3oz of the base into 6 ramekins. Place the ramekins in the steamer and turn the heat down to low. Cook the custards for 13 minutes, until they are firm to the touch and still jiggle. The custards will look a strange grey color if you look into the steamer before they are fully cooked.
Roasted Corn Cob Stock
8 corn cobs (smoked would be better)
800 grams water
1 4 inch piece Kombu
2 cloves garlic
Cut the top and bottom off the 8 ears of corn and discard. Cut each corn cob in half and put on a parchment lined baking pan. Roast the cobs at 425°F for thirty minutes or until foxy brown. Remove the cobs from the oven and put them in a pressure cooker. Add the water, kombu and garlic and cook on high pressure for 20 minutes. Let the pressure dissipate naturally. Strain the corn stock and reserve.